We are examining the cellular and molecular changes in primates after Gruntzig injury (comparable to angioplasty) of animals that have been on a hypercholesterolemic diet for two years to create advanced lesions of atherosclerosis. Restenosis after angioplasty continues to be a problem in 30-40% of patients treated for occlusive vessels. Most attempts to evaluate restenosis after angioplasty have been based on studies in the normal rat carotid artery, which is very different from treatment of the human problem. Our goal is to evaluate restenosis postangioplasty in a model that is more relevant to the clinical situation in humans. We are in the process of evaluating tissue from 10 animals that were sacrificed 2 days to 3 months after Gruntzig injury. We have also evaluated the extent of lesion formation and acute events postangioplasty by monitoring the animals with magnetic resonance imaging, a noninvasive procedure. The imaging data will be correlated with pathologic analysis of tissue from these animals.